How gene linked to autism, Tourette's impacts brain

Researchers have discovered how a genetic alteration that increases the risk of developing Autism and Tourette's impairs brain communication.

People with a genetic deletion known as chromosome 2p16.3 deletion often experience developmental delay and have learning difficulties.

They are also around 15 times more likely to develop Autism and 20 times more likely to develop Tourette's Syndrome, but the mechanisms involved are not completely understood.

Using brain imaging studies, neuroscientists showed that deletion of the gene impacted by 2p16.3 deletion (Neurexin1) have impacts on the function of brain regions involved in both conditions.

This genetic deletion disrupts a brain area known as the Thalamus, compromising its ability to communicate with other brain areas, said the study published in the journal Cerebral Cortex.

"We currently have a very poor understanding of how the 2p16.3 deletion dramatically increases the risk of developing these disorders," said lead researcher Neil Dawson of Lancaster University in Britain.

"However, we know that the 2p16.3 deletion involves deletion of the Neurexin1 gene, a gene that makes a protein responsible for allowing neurons to communicate effectively," Dawson said.

Deletion of the Neurexin1 gene affects brain areas involved in Autism and Tourette's including the Thalamus, a collection of brain regions that play a key role in helping other brain areas communicate with each other.

Changes were also found in brain regions involved in processing sensory information and in learning and memory.

Importantly, the researchers also found that the ability of the Thalamic brain regions to communicate with other brain areas was impaired by the genetic deletion.

They then tested the ability of a low dose of the drug Ketamine, which is used clinically at higher doses as an anesthetic, to normalise the alterations in brain function induced by genetic deletion.

"Intriguingly our data suggest that Ketamine can restore some aspects of the brain dysfunction that results from 2p16.3 deletion and suggests that ketamine, or other related drugs, may be useful in treating some of the symptoms seen in autism and Tourette's," Dawson said.